This invention relates generally to mail handling systems, and, more particularly to a system for reorienting a moving stream of generally flat articles.
In the field of automated mail processing, there are numerous inventions and machines designed to handle uniformly dimensioned articles, typically known as first class mail, ranging in size from post cards to business letter envelopes. There are, however, a limited number of machines designed to automate the processing of larger flat articles otherwise known as xe2x80x9cmail flats,xe2x80x9d which may be up to fifteen inches square and one and a quarter inches thick.
Current practices in automated mail handling include the placement of batches of flat mail, or mail flats, into feeders, which separate the individual pieces and expel those pieces in a serial stream having a vertical orientation and a predetermined periodicity or pitch between the leading edges of adjacent pieces. The mail flats in this vertically oriented stream are then reoriented and placed on a horizontal conveyor with another predetermined periodicity, for the purpose of further handling and processing. This reorientation process can be particularly challenging for several reasons.
One challenge to the reorientation process is the handling of magazines and newspapers. Magazines must be automatically handled by their bound edge, and newspapers must be handled along their final fold. This requirement is critical to achieving any sort of speed in the automatic handling process. For this reason, these articles are placed in the feeder bin with the bound edge or final fold facing downward and are expelled from the feeder in this orientation. Later, when magazines and newspapers are placed on the horizontal conveyor, they must have their bound edge or final fold facing forward for proper handling. Therefore, the reorientation step must be performed so that the bottom edge of the vertically oriented mail flats becomes the leading edge of the horizontally oriented mail flats.
Space constraints are another challenge in the reorientation process. Input feeders typically have maximum height, ergonomic limitations to allow an operator to conveniently and safely place stacks of mail into the feeder. The horizontal output conveyors typically have minimum height requirements for receiving the mail flats because of similar constraints in removing objects. Therefore, the reorientation apparatus is limited in the amount of height that it can use for the reorientation process. The height restriction is further aggravated by the size and nature of the mail flats to be handled. As mentioned, such mail flats may be up to 15 inches by 15 inches, with thicknesses up to 1_inches. Automatically reorienting a stiff 15xc3x9715xc3x971.25 inch parcel is much more challenging than reorienting a flexible magazine.
Mail processing machinery also needs to operate at a sufficient throughput, commonly measured as xe2x80x9cpieces per hourxe2x80x9d (pph), that is economically viable for the mail handling agency to sacrifice the electrical power and space requirements as well as justify the capital expenditure. The machinery must also have sufficient throughput and accuracy to justify replacement of manual labor.
A common method of handling mail is from a horizontally oriented conveyor. The horizontal conveyor affords the easiest means for handling mail flats. Also, various other devices, such as scanners, cameras and sorters, have already been designed to work with such conveyors. A key hurdle in designing systems is how to achieve high throughput without adjacent pieces colliding with each other. U.S. Pat. No. 5,860,504 discloses machinery that places mail flats on a horizontal conveyor using multiple input feeders, which individually sense open spaces on the horizontal conveyors and then deliver their individual pieces to the sensed openings. The mail flats being handled have already been reoriented for proper placement on the horizontal conveyor.
In one embodiment, the present invention provides a system for reorienting flat articles in a serial stream including a conveyor mechanism for receiving a horizontally moving, serial input stream of substantially vertically oriented flat articles, which each have a downwardly oriented primary edge, and having a diverter gate for laterally directing the flat articles alternately between two separate output paths. A separate pocket is coupled to each separate output path for impeding horizontal movement of each flat article and for positively engaging and accelerating each flat article in the direction of its primary edge. A separate channel is coupled to each pocket to deliver the substantially horizontally oriented flat articles from each pocket.
In a refinement of the above invention, each separate output path of the conveyor mechanism is adapted for imparting rotational movement to each flat article therein.
In a separate refinement, each pocket includes a drive mechanism to pressure flat articles on opposing flat sides to positively engage and accelerate the flat articles. In this manner, a control system may be used to control at least one of the pockets for causing flat articles to be delivered from both channels at regular intervals.
In a further separate refinement, each channel includes a driven conveyor having a lower, flexible belt conveyor to support flat articles along the entire length of the channel and an upper, flexible belt conveyor adapted to place force on the lower, flexible belt conveyor and flat articles in the channel.
The method of the present invention covers reorienting flat articles in a serial stream, including the steps of: receiving a horizontally moving, serial input stream of substantially vertically oriented, flat articles each having a downwardly oriented primary edge; laterally diverting the flat articles in the serial input stream, alternately between a pair of separate paths; impeding horizontal movement of each flat article in each separate path; accelerating each flat article with impeded horizontal movement in the direction of its primary edge; and delivering substantially horizontally oriented flat articles from each separate path.